OT: Using the 12V line from a computer PS to replace 'bricks'

[Andrew]

I am considering upgrading my AMD phenon PC to have an 80+ gold power supply, something like a Corsair TX550M.

This will have far more power than needed, and there are about

4 'bricks' plugged in next to it to supply a netgear GS105 switch, a single disk NAS box, a USB hub and a canon pixma 1200 printer.

I was thinking of fitting some suitable chassis power sockets into one of the 5.25 blanking plates above the CD rom and powering all these devices from the 12V line of the computer PS. It has on board graphics and sound, so the main draw is processor and Asus DVD rom M-drive.

Any thoughts ?. Some inline fuses maybe ?. take great care to get the polarity right :-). ?.

The NAS box has a tubular 'device' about 2 inches from the concentric plug, which I assume is a ferrite device. Since the Corsair PS has a nice clean 12v line, would I need to worry about this ?. I don't want to chop the cables on the existing bricks,, I'll get some replacement cables.

[Alan Dawes]

From the experience of having to pay over £400 to recover data due to the main computer and the backup drives sharing the same power supply which failed sending a pulse through all the drives that burnt out their heads. My advice is NEVER EVER share a PSU between your computer and backup drives eg in your NAS.

Alan

[tabbypurr]

£8.19 delivered yrfstIUT65y7hoCC2Hw_wcB

It's a good bet that those power ratings are unrealistic.

Printers typically require much higher voltage. Anything else that runs on

5v/12v can do so.

yup

does it? What noise level does your scope show?

One thing's for sure, spending time worrying about the existence of ferrite s is not going to be time well spent.

Share away. When you've done each backup, remove the backup drive from both usb & power then it's immune to that kind of thing. Obviously you have mor e than one backup.

NT

[Andrew Gabriel]

I do this - actually I extend a spare drive connector out of the case to a power distribution board which Maplin used to sell (but no longer do) with lots of 5V and 12V sockets. This powers a hand full of devices.

One thing you need to be aware of is the linking of grounds via the shared power. For ethernet connected devices, this is not a problem as all ethernet ports are DC isolated. If you have a device connected via USB, serial, parallel, etc, where the -ve power conductor isn't the device's 0V rail, then you will likely damage the connection ports on the device and/or the computer.

I also would not do this for a device connected to an external telephone line.

The ferrite device is to stop the power cord acting as a transmitter aerial due to RF frequences used in the device bleeding back into the power cord. The impact of not having it could be poor radio reception, so you can test if this is a problem by tuning a radio into a week station, and make sure switching on the device doesn't interfere. Check on AM and FM. These are often added when the device goes for EMC testing and fails due to emitted RF.

[dennis]

The ferrite is probably to stop the NAS radiating interference from the mains cable rather than to stop it getting into the NAS.

If the NAS is your backup device you don't want it in the same building and certainly not on the same PSU. Put it in the shed or garage or next door where it can't get stolen with your PC or burnt or flooded, etc.

[Adrian Caspersz]

In winter, run some heavy CPU intensive stuff and with near 100% efficiency it will heat up your room.

and there are about

Best run 24/7 for other device connectivity

a single disk NAS box,

Best run 24/7, located somewhere else.

a USB hub

Do-able, but probably has a 6V supply. I'd use a cheap ebay buck regulator with an 7 segment LED so you can admire the power consumption of your USB gadgets.

and a canon

Nope. The K30297 PSU in that kicks out 24V, standby is 1W.

[Lee]

Absolutely you want to think about fusing, 45A could cause some issues if there is a problem :) You want to make sure whatever connectors and wiring you use are up to the job as well.

Otherwise, yeah shared grounds and single point of failure as noted by others.

[Lee]

Thought I 'd better add, from a reliability aspect, not so much current carrying. There are enough pictures of burnt molex and motherboard connectors from them simply being loose or dirty.